One large community of people had retreated to what was left of the oceans, sheltering from the heat there. But even the marine invertebrates were choking on ash. And the volcanism had polluted the water with exotic trace elements — like cadmium and mercury and iridium and osmium — and the oceans, the birthplaces of life on Earth, were, in their last days, becoming toxic.

But, in a way, it was geologist’s heaven. Processes that ought to take millions of years were occurring in mere years, even months. As if the Earth was trying to cram in her best special effects while she still had time. Geology, overwhelmed with unwelcome evidence, was at last becoming a mature science — just as, so he heard, fundamental physics had been galvanized by the study of the Moonseed processes, so that whole new areas of theory and technological achievement were being opened up.

None of it any use, though, in stitching poor Earth back together.

Dear Jane had called the sites of the great magma plumes Earth’s chakras. The energy centres, the wheel of light from which Earth’s energies were bleeding away. It was as good a description as any.

He stepped forward cautiously, keeping an eye on the compass set into his chest pack. The compass was inertial, a little spinning gyroscope system, like they used to use in aircraft and spaceships. It was the only type that was reliable nowadays; the electronic kind that communicated with the GPS satellites was too easily thrown out by the auroras and the big electrical storms that flapped around the planet, and you couldn’t use a magnetic compass, of course, since Earth’s magnetic field had gone to hell. The geophysicists said it was all to do with the melting of the ice caps and the oceans” evaporation, all that mass redistribution making Earth wobble like a kid’s top after a hefty kick. The reversals in the magnetic field’s polarity were coming about once a year now, thus screwing up the magnetosphere and letting through the cosmic rays, just adding to the fun down here, and coincidentally fouling up Henry Meacher’s map-reading…

But he couldn’t make head or tail of this damn astronaut’s compass.

Well, maybe it was a little brighter to his left, to the east, where the sun must be rising. Maybe there were miles of cloud above him, the evaporated oceans lofted into the sky; maybe his green Earth had turned to a pearly white ball like Venus had been, where an American needed a space suit to walk out of the big underground shelters; but as far as he knew the world was still spinning the right way.

Anyhow, he might get lost, but wasn’t going to come to any harm, on this plain of mud.

He stepped forward, carefully.

…It still seems remarkable to me to see Nadezhda bounding around in the low gravity without an ounce of self-consciousness.